Metal rings formed from beryllium-copper alloys

ABSTRACT

Processes are disclosed for forming beryllium-copper metal rings having a fine and uniform grain structure. A raw BeCu casting is pre-forged and turned to form a BeCu billet. The BeCu billet is subjected to various heat treatment and cooling cycles to obtain/maintain combinations of advantageous material properties. Generally, the BeCu billet is preheated, hot worked via forging, heated again, hot worked again via ring rolling followed by air cooling, solution annealed followed by quenching, and heated a final time followed by air cooling.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/587,533, filed Nov. 17, 2017, which is fully incorporated byreference herein.

BACKGROUND

The present disclosure relates to metal rims or rings that are used forcasting amorphous metals. In particular, the rings of the presentdisclosure are made from beryllium-copper alloys. Processes for makingthe same are disclosed, and will be described with particular referencethereto.

Beryllium-copper (“BeCu”) alloys are notable for their superiorcombination of thermal conductivity, strength, toughness, impact energyand resistance to corrosion. Additional benefits of BeCu alloys includea relatively high electrical conductivity, ultrasonic inspectability andgood thermal management. This combination of properties has made BeCualloys desirable for a wide range of applications. However, moreeconomical processing of BeCu alloys is sought.

Conventional metal rings have experienced problems related to surfacequality longevity, ductility, formability, ultrasonic inspectability,conductivity, and lack of grain size refinement. The metal ringsdisclosed herein address these issues while easing product manufactureand reducing costs.

BRIEF DESCRIPTION

The present disclosure relates to BeCu metal rings having a fine anduniform grain structure as well as processes for forming the same. A rawBeCu casting is pre-forged and turned to form a BeCu billet. In general,heat treatment and cooling cycles are performed to achieve materialproperties which permit the rings to maintain surface quality for longperiods of time, while at the same time enabling customers to gainhigher productivity from each casting ring. Very broadly, the BeCubillet is preheated, hot worked via forging, heated again, hot workedagain via ring rolling followed by air cooling, solution annealedfollowed by quenching, and heated a final time followed by air cooling.

Disclosed in various embodiments herein are processes for making metalrings which include providing a billet made from a BeCu alloy. Thebillet is preheated at a temperature of about 800° C. to about 850° C.,including about 820° C., for a period of at least 8 hours. The billet isthen hot worked by forging the billet into a ring-shaped preform at atemperature of about 750° C. to about 850° C. The forging can includepress forging and piercing to create the ring-shaped billet.

Next, the preform is soaked at a temperature of about 815° C. to about835° C., including about 820° C. This soaking can be done for a periodof at least 2 hours, or at least 8 hours. In some particularembodiments, the preform is soaked for a period of at least 8 hours ifthe preform has cooled to a temperature of about 600° C. or less. Thepreform is then hot worked again via ring rolling the preform at atemperature of about 750° C. to about 850° C. to form a ring having awall thickness, which desirably is substantially uniform about thecircumference of the ring.

After ring rolling, the ring is air cooled. The ring is then solutionannealed at a temperature of about 780° C. to about 800° C. for a periodof at least 1.5 hours. Immediately following solution annealing, thering is quenched in a quench medium (such as water). Generally, thequench medium has a maximum temperature of about 40° C. before thequenching and a maximum temperature of about 50° C. after the quenching.The ring is then age hardened by heat treating at a temperature of about385° C. to about 400° C. for a period of about 3 hours. In particularembodiments, the about 3 hour period begins at a temperature of about393° C., and the temperature is raised to about 400° C. The 400° C.temperature is then maintained for the remaining period of time. Afterheat treating, the ring is air cooled.

In some embodiments, mechanical machining can be performed on the ringto achieve a final desired shape.

The BeCu alloy used to make the metal ring has a beryllium content offrom about 1.6 wt % to about 2.0 wt %, including from about 1.8 wt % toabout 2.0 wt % and from about 1.6 wt % to about 1.85 wt %. In someparticular embodiments, the BeCu alloy has a beryllium content of fromabout 1.8 wt % to about 1.9 wt %. The balance of the BeCu alloy isusually copper. In some embodiments, the BeCu alloy further comprisesfrom about 0.2 wt % to about 0.3 wt % cobalt; or further comprises fromabout 0.2 wt % to about 0.6 wt % lead; or further comprises an amount ofnickel, cobalt, and optionally iron such that the sum of (nickel+cobalt)is about 0.2 wt % or higher, and the sum of (nickel+cobalt+iron) isabout 0.6 wt % or less.

In some embodiments, the hot working achieved by the ring rollingreduces the wall thickness by at least 50%. In further embodiments, atotal reduction in wall thickness of at least 70% or greater is achievedover the entire process (i.e. all process steps).

The solution annealing can be performed for a period of about 30 minutesfor approximately every 25 millimeters (mm) of wall thickness of thering.

Disclosed in additional embodiments herein are metal rings made by theprocesses described above. The metal rings are made from a BeCu alloyhaving a beryllium content of from about 1.6 wt % to about 2.0 wt %,including from about 1.8 wt % to about 2.0 wt % and from about 1.8 wt %to about 1.9 wt %, the balance being substantially copper. The BeCumetal rings further have a 0.2% offset yield strength of at least 760MPa; a Rockwell C hardness of at least 27 HRC; a percent elongation ofat least 6%; an electrical conductivity of at least 25% IACS; and/or anaverage grain size of less than 0.1 mm.

These and other non-limiting characteristics of the disclosure are moreparticularly disclosed below

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings, which arepresented for the purposes of illustrating the exemplary embodimentsdisclosed herein and not for the purposes of limiting the same.

FIG. 1 is a flow chart for a first exemplary process of making a metalring from a beryllium-copper (“BeCu”) alloy including various heattreating and cooling steps.

FIG. 2 is a flow chart for a second exemplary process of making a metalring from a BeCu alloy including various heat treating and coolingsteps.

FIG. 3 is an illustration of a rolling operation which utilizes anexemplary ring rolling mill used to form the BeCu metal rings disclosedherein.

FIG. 4 is a cross-section view of an exemplary BeCu metal ring preformformed by the processes disclosed herein.

DETAILED DESCRIPTION

A more complete understanding of the components and processes disclosedherein can be obtained by reference to the accompanying drawings. Thesefigures are merely schematic representations based on convenience andthe ease of demonstrating the present disclosure, and are, therefore,not intended to indicate relative size and dimensions of the devices orcomponents thereof and/or to define or limit the scope of the exemplaryembodiments.

Although specific terms are used in the following description for thesake of clarity, these terms are intended to refer only to theparticular structure of the embodiments selected for illustration in thedrawings, and are not intended to define or limit the scope of thedisclosure. In the drawings and the following description below, it isto be understood that like numeric designations refer to components oflike function.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise.

As used in the specification and in the claims, the term “comprising”may include the embodiments “consisting of” and “consisting essentiallyof.” The terms “comprise(s),” “include(s),” “having,” “has,” “can,”“contain(s),” and variants thereof, as used herein, are intended to beopen-ended transitional phrases, terms, or words that require thepresence of the named components/steps and permit the presence of othercomponents/steps. However, such description should be construed as alsodescribing compositions or processes as “consisting of” and “consistingessentially of” the enumerated components/steps, which allows thepresence of only the named components/steps, along with any impuritiesthat might result therefrom, and excludes other components/steps.

Numerical values in the specification and claims of this applicationshould be understood to include numerical values which are the same whenreduced to the same number of significant figures and numerical valueswhich differ from the stated value by less than the experimental errorof conventional measurement technique of the type described in thepresent application to determine the value.

All ranges disclosed herein are inclusive of the recited endpoint andindependently combinable (for example, the range of “from 2 grams to 10grams” is inclusive of the endpoints, 2 grams and 10 grams, and all theintermediate values).

The term “about” can be used to include any numerical value that canvary without changing the basic function of that value. When used with arange, “about” also discloses the range defined by the absolute valuesof the two endpoints, e.g. “about 2 to about 4” also discloses the range“from 2 to 4.” The term “about” may refer to plus or minus 10% of theindicated number.

The present disclosure refers to steps for processing a metalalloy/article which occur at specified temperatures. It is noted thatthe temperatures referred to herein are the temperature of theatmosphere to which the metal alloy is exposed, i.e. the temperature towhich the heating device (e.g. a furnace) is set. The metal alloy itselfdoes not necessarily reach these temperatures.

The present disclosure refers to a “uniform” wall thickness. This termpermits the wall thickness to vary, and should be understood to includenumerical values which are the same when reduced to the same number ofsignificant figures and numerical values which differ from the statedvalue by less than the experimental error of conventional measurementtechniques.

Metal rims or rings are used in processes and equipment related toindustrial machinery, wind power plants, high-power gears, offshoretechnology, rings and supporting rings for slewing bearings, turbines,generators, transformers, hydraulic motors, valves, pipelines, textilemachinery, tanks/pressure vessels, gear rings, aerospace andspaceflight, bulk-feed presses, steel mills, including but not limitedto use for bearings, clutches, couplings, drives, flanges, etc. However,conventional rings wear quickly, which increases the number of ringsthat need to be purchased each year.

The beryllium-copper rings disclosed herein are produced by novel heattreatment processes which impart material properties that allow thesurface of the ring to achieve more stability for a longer period oftime and allow more metal to be cast across the ring before having tore-machine to surface or purchase a replacement ring. In particular, thepresently disclosed metal rings are made from a beryllium-copper(“BeCu”) alloy which provides a combination of properties amenable toenhancement by the heat treatment and quench/cooling cycles described infurther detail below. Such enhanced properties include but are notlimited to yield strength, hardness, ductility, electrical conductivity,fine and uniform grain structure, and ultrasonic inspectability. Thefine and uniform grain structure and maximum conductivity are producedby over-aging and excessive solution annealing followed by cascadingover-aging process steps.

With reference to FIG. 1, an exemplary process (S100) of making a metalring including various heat treatment and quenching/cooling cyclesaccording to a first embodiment starts at S101. At S102, a BeCu metalalloy billet is provided or received. At S104, the billet is preheatedat a temperature of about 800° C. to about 850° C., including about 820°C., for a period of at least 8 hours. This preheating step is intendedto obtain as uniform a temperature as possible throughout the thicknessof the billet, so that the subsequent step uniformly affects all of themetal alloy in the billet.

At S106, the billet is hot worked into a ring-shaped preform. Inparticular, the billet is forged into the ring-shaped preform. Hotworking is a metal forming process in which the cross-section of thealloy is reduced to make the desired shape and dimension, at atemperature generally above the recrystallization temperature of thealloy. This generally reduces directionality in mechanical properties,and produces a new equiaxed microstructure.

Forging is a process by which workpiece thickness is compressed byapplication of heat and pressure, which expands its cross section orotherwise changes its shape. This plastically deforms the alloy, and isgenerally performed above the recrystallization temperature. Thisimproves mechanical properties, improves ductility, further homogenizesthe alloy, and refines coarse grains.

During forging, the hot work must generally be maintained within acontrolled temperature range to avoid forging defects. For example,excessively high temperatures may result in incipient melting, andexcessively low temperatures may result in surface cracking. In anyevent, the forging temperature should be high enough to allowrecrystallization without promoting excess microstructural grain growth.Accordingly, the hot working of S106 is performed at a temperature ofabout 750° C. to about 850° C. Preferably, a temperature of about 770°C. to about 834° C. is maintained during hot working.

This first hot working step can be performed by various forging steps,including but not limited to press forging and piercing. Press forgingrefers to the slow and continuous application of pressure on the BeCubillet. In particular, press forging generally includes upsetting of theBeCu billet, where pressure acts on the longitudinal axis of the billet,causing the billet to form into a pancake shape. Upsetting also resultsin directional grain flow within the billet. During piercing, a hole iscut in the middle of the BeCu billet that has been flattened duringpress forging. As a result of piercing, the BeCu billet is transformedinto a ring-shaped preform, wherein the ring shape is generally toroidalor “doughnut-like.” Punching can optionally be performed in place of orin combination with piercing, where a punch removes a slug from themiddle portion of the BeCu billet.

At S108, the preform is soaked at a temperature of about 815° C. toabout 835° C., including about 820° C. Again, this is intended to obtainas uniform a temperature as possible throughout the thickness of thebillet for subsequent processing. This soaking generally occurs for atleast 2 hours, and in some embodiments may occur for at least 8 hours.In particular embodiments, the soaking occurs for a period of about 2hours to about 8 hours.

At S110, ring rolling is performed on the preform at a temperature ofabout 750° C. to about 850° C. to form a ring having a uniform wallthickness, followed by air cooling. The temperature should be maintainedduring the entire ring rolling step. The ring rolling is preferablyperformed at a temperature of about 770° C. to about 834° C. The ringrolling reduces the wall thickness by at least 50%. In other words, thehot work forging performed on the ring-shaped preform generally reducesthe area of the casting by at least 50%.

Following the ring rolling, the ring is air cooled. In this regard, theBeCu ring is removed from the furnace and exposed to ambienttemperature. If desired, air cooling can be active, i.e. ambient air isblown towards the ring.

At S112, the ring is solution annealed at a temperature of about 780° C.to about 800° C. for a period of at least 1.5 hours. In general, thesolution annealing of S112 should be performed for a period of about 30minutes for approximately every 25 mm of ring wall thickness.

The solution annealing is immediately followed by quenching the ring ina quench medium at S114. The quench medium should have a maximumtemperature of about 40° C. before the quenching and a maximumtemperature of about 50° C. after the quenching. This type of quenchingquickly changes the temperature of the BeCu ring, and generally resultsin a single phase.

At S116, the ring is age hardened by heat treating at a temperature ofabout 385° C. to about 400° C. for a period of about 3 hours, followedby air cooling. Mechanical machining of the ring can optionally beperformed at S118. As a result of these steps, a BeCu metal ring with afine uniform grain size is formed.

With reference to FIG. 2, another exemplary process (S200) of making ametal ring according to a second embodiment starts at S201. At S202 aBeCu metal alloy billet is provided. At S204, the billet is preheated ata temperature of about 800° C. to about 850° C., including about 820°C., for a period of at least 8 hours. At S206, the billet is hot workedinto a ring-shaped preform. Again, the hot work must generally bemaintained within a controlled temperature range to avoid forgingdefects as discussed above. Accordingly, the billet is forged into thering-shaped preform at a temperature of about 750° C. to about 850° C.Preferably, a temperature of about 770° C. to about 834° C. ismaintained during hot working.

At S208, if the preform has cooled to a temperature of about 600° C. orless, the preform is soaked at a temperature of about 815° C. to about835° C., including about 820° C., for a period of about 8 hours,including at least 8 hours. At S210, ring rolling is performed on thepreform at a temperature of about 750° C. to about 850° C. to form aring having a uniform wall thickness, followed by air cooling. Again,the ring rolling is preferably performed at a temperature of about 770°C. to about 834° C. At S212, the ring is solution annealed at atemperature of about 780° C. to about 800° C. for a period of at least1.5 hours. In general, the solution annealing of S212 is performed for aperiod of about 30 minutes for approximately every 25 mm of ring wallthickness.

The solution annealing is immediately followed by quenching the ring ina quench medium at S214. The quench medium is usually water. The quenchmedium should have a maximum temperature of about 40° C. before thequenching and a maximum temperature of about 50° C. after the quenching.

At S216, the ring is age hardened by heat treating at a temperature ofabout 385° C. to about 400° C. for a period of about 3 hours, followedby air cooling. Mechanical machining of the ring can optionally beperformed at S218. A BeCu amorphous metal ring with a fine uniform grainsize is formed.

In particular embodiments illustrated by FIG. 1 and FIG. 2, during theheat treating step (S116, S216), the about 3 hour period begins at atemperature of about 393° C. The temperature is raised to about 400° C.,and the temperature is maintained at this temperature for the remainingperiod of time.

More generally, the processes illustrated in FIG. 1 and FIG. 2 arerelated to making a BeCu ring having a fine uniform grain size. A rawBeCu casting is pre-forged and turned into a billet from which the ringis made. The BeCu metal alloy billet is provided (S102, S202). Thebillet is preheated to a first temperature of from about 800° C. toabout 850° C., including about 820° C., for a first time period of atleast 8 hours (S104, S204). A first hot work forging of the billet isperformed to create a ring-shaped preform (S106, S206). The ring-shapedpreform is then soaked at a second temperature of from about 815° C. toabout 835° C. for a second time period of at least 2 hours (S108, S208).A second hot work forging is performed by ring rolling, followed by aircooling, to form a ring having a uniform wall thickness (S110, S210).The ring is then exposed to a third temperature of from about 780° C. toabout 800° C. for a third time period (S112, S212). Immediately afterthe third temperature and third time period, the ring is cooled byquenching (S114, S214). The ring is then heated to a fourth temperaturewhich is less than the first, second, and third temperatures and for afourth time period, followed by air cooling to a final ambienttemperature to produce the ring (S116, S216) with a fine uniform grainsize. If desired, mechanical machining can be performed on the ring at(S118, S218). Mechanical machining may include but is not limited tosawing, drilling, tapping, boring, milling, turning, grinding,burnishing, reaming, electrical discharge machining (“EDM”) etc., inorder to achieve a desired final shape for the BeCu metal ring. Thefinal shape of the BeCu metal ring may be based on the application inwhich the ring is used.

The processes illustrated in FIG. 1 and FIG. 2 generally result in atotal reduction in wall thickness of at least 70%. In general, thereduction ratio for the BeCu ring-shaped preform should be large enoughto allow the deformation to penetrate the entire work section. Partialpenetration, particularly on the final passes of ring rolling, will notproduce the desired uniform dynamic recrystallization in the BeCu ring.Insufficient deformation may result in nonuniformity in microstructureand mechanical properties after the age hardening in process steps(S116, S216).

The degree of reduction can be determined by measuring the change in thecross-sectional area of the ring wall before and after hot ring rolling,or before preheating and after heat treating or optional finishing,according to the following formula:

% HW=100*[A ₀ −A _(f) ]/A ₀

where A₀ is the initial or original cross-sectional area before hotworking, and A_(f) is the final cross-sectional area after hot working.It is noted that the change in cross-sectional area is usually duesolely to changes in the thickness of the alloy, so the % HW can also becalculated using the initial and final thickness as well.

Furnaces used in the heat treatment processes described hereinpreferably meet the requirements of AMS2750 or the NORSOK equivalent forpyrometry. The solution annealing of process steps (S112, S212) arepreferably performed in a Class 5 furnace, and more preferably in aClass 2 furnace. The age hardening or heat treating steps of (S116,S216) are preferably performed in a Class 2 furnace. Furnace classdefinitions are delineated in AMS2750 or the NORSOK equivalent.

In both embodiments illustrated by FIG. 1 and FIG. 2, the second hotwork forging (S110, S210) is generally performed by ring rolling on arolling mill. An exemplary ring rolling operation 300 including ringrolling mill 302 is illustrated in FIG. 3. During ring rolling, the BeCuring-shaped preform 304 is placed over an idler roll 306. The idler roll306 is generally disposed within the hollow central portion 308 of thering-shaped preform 304 and acts against an inner surface 310 ordiameter thereof. A drive roll 312 is generally disposed against anouter surface 314 or diameter of the ring-shaped preform. An upper axialroller 316 is disposed against a top surface 320 of the preform. A loweraxial roller 318 is disposed against a bottom surface 322 of thepreform.

Pressure is continuously applied to the preform 304 by the idler roll306, the drive roll 312, the upper axial roller 316, and the lower axialroller 318. The pressure is continuously applied until the desired innerdiameter, outer diameter, height, and/or wall thickness of the ring isachieved. Generally, the ring rolling is performed with the goal ofthoroughly working the ring cross-section as uniformly as practical tominimize grain size differences after recrystallization. An averagegrain size of less than about 0.1 mm is desirable.

FIG. 4 is a cross-sectional view of the preform 304, which can alsorepresent the finished ring. The preform has an inner diameter D_(i) andan outer diameter D_(o). The wall thickness T of the ring is thedifference between the two diameters. The ring also has a height H. Thediameters are measured from center axis 305.

In some embodiments, the BeCu ring may have an outer diameter D_(o) offrom about 250 mm to about 8,000 mm, including from about 350 mm toabout 2,000 mm. The inner diameter D_(i) of the BeCu ring may be atleast about 150 mm to about 350 mm. The BeCu ring generally has a wallthickness T of less than about 700 mm to about 800 mm. The height H ofthe BeCu ring is generally from about 20 mm to about 900 mm, includingfrom about 200 mm to about 300 mm.

The inner surface 310 is generally smooth. The outer surface 314, theupper surface 320, and the lower surface 322 are shown as being flat,though they can be shaped as desired for the application/device forwhich the ring is to be used.

As a result of the exemplary process steps described above, a metal ringmade of BeCu is formed having a variety of advantageous properties.These advantageous properties include but are not limited to strength,hardness, ductility, electrical conductivity, and refined grain size. Inparticular, the advantageous properties include any combination of a0.2% offset yield strength of at least 760 MPa; a Rockwell C hardness ofabout 27 HRC to about 33 HRC; a percent elongation of at least 6%; anelectrical conductivity of at least 25% of the International AnnealedCopper Standard (“IACS”, where 100% IACS is equal to 5.8×10⁷Siemens/meter or 1.72 micro-ohm-cm); and an average grain size of lessthan 0.1 mm. The average grain size is measured in the axial directionon a slice taken from the rolled ring and on the inside face of theslice closest to the finished part. The 0.2% offset yield strength ismeasured according to ASM E8. The Rockwell C hardness is measuredaccording to ASTM E18. The % elongation is measured according to ASTME3. The electrical conductivity is measured according to ASTM E1004.

The BeCu alloy used to form the metal ring comprises about 1.6 wt % toabout 2.0 wt % beryllium, including from about 1.8 wt % to about 2.0 wt% and from about 1.8 wt % to about 1.9 wt % beryllium.

The BeCu alloy can also include small amounts of cobalt (Co), nickel(Ni), iron (Fe), and/or lead (Pb). In some embodiments, the BeCu alloymay further comprise from about 0.2 wt % to about 0.3 wt % cobalt. Instill other embodiments, from about 0.2 wt % to about 0.6 wt % lead maybe included in the BeCu alloy.

In other embodiments, the sum of cobalt and nickel in the BeCu alloy isat least 0.2 wt %. In other embodiments, the sum of cobalt, nickel, andiron in the BeCu alloy is at most 0.6 wt %. It should be noted that thisdoes not require all three elements to be present. Such alloys couldcontain at least one of nickel or cobalt, but could potentially containonly nickel or cobalt. The presence of iron is not required, but in someparticular embodiments iron is present in an amount of about 0.1 wt % ormore (up to the stated limit).

In some particular embodiments, the BeCu alloy comprises about 1.8 wt %to about 2.0 wt % beryllium; a sum of cobalt and nickel of at least 0.2wt %; a sum of cobalt, nickel, and iron of at most 0.6 wt %; and balancecopper. This alloy is commercially available from Materion Corporationas Alloy 25. Alloy 25 has an elastic modulus of about 131 GPa; densityof about 8.36 g/cc; a thermal conductivity at 25° C. of about 105W/(m·K); 0.2% offset yield strength of about 130 MPa to about 280 MPabefore heat treatment; minimum ultimate tensile strength of about 410MPa before heat treatment; and minimum 35% elongation before heattreatment.

In some particular embodiments, the BeCu alloy comprises about 1.6 wt %to about 1.85 wt % beryllium; a sum of cobalt and nickel of at least 0.2wt %; a sum of cobalt, nickel, and iron of at most 0.6 wt %; and balancecopper. This alloy is commercially available from Materion Corporationas Alloy 165. Alloy 165 has an elastic modulus of about 131 GPa; densityof about 8.41 g/cc; a thermal conductivity at 25° C. of about 105W/(m·K); 0.2% offset yield strength of about 130 MPa to about 280 MPabefore heat treatment; minimum ultimate tensile strength of about 410MPa before heat treatment; and minimum 35% elongation before heattreatment.

In other embodiments, the BeCu alloy comprises about 1.6 wt % to about2.0 wt % beryllium; about 0.2 wt % to about 0.3 wt % cobalt; and balancecopper. This alloy is commercially available from Materion Corporationas MoldMax HH® or MoldMax LH®.

MoldMax HH® has an elastic modulus of about 131 GPa; density of about8.36 g/cc; and thermal conductivity at 25° C. of about 130 W/(m·K); 0.2%offset yield strength of about 1000 MPa; a typical ultimate tensilestrength of about 1170 MPa; and a typical 5% elongation.

MoldMax LH® has an elastic modulus of about 131 GPa; density of about8.36 g/cc; and thermal conductivity at 25° C. of about 155 W/(m·K); 0.2%offset yield strength of about 760 MPa; a typical ultimate tensilestrength of about 965 MPa; and a typical 15% elongation.

In other particular embodiments, the BeCu alloy comprises about 1.8 wt %to about 2.0 wt % beryllium; a sum of cobalt and nickel of at least 0.2wt %; a sum of cobalt, nickel, and iron of at most 0.6 wt %; from about0.2 wt % to about 0.6 wt % lead; and balance copper. This alloy iscommercially available from Materion Corporation as Alloy M25. Alloy M25has an elastic modulus of about 131 GPa; density of about 8.36 g/cc; athermal conductivity at 25° C. of about 105 W/(m·K); 0.2% offset yieldstrength of about 130 MPa to about 250 MPa before heat treatment;minimum ultimate tensile strength of about 410 MPa before heattreatment; and minimum 20% elongation before heat treatment.

In some particular embodiments, the BeCu alloy comprises about 1.8 wt %to about 2.0 wt % beryllium; a sum of cobalt and nickel of at least 0.2wt %; a sum of cobalt, nickel, and iron of at most 0.6 wt %; and balancecopper. This alloy is commercially available from Materion Corporationas Alloy 190. Alloy 190 has an elastic modulus of about 131 GPa; densityof about 8.36 g/cc; and a thermal conductivity at 25° C. of about 105W/(m·K).

In some particular embodiments, the BeCu alloy comprises about 1.8 wt %to about 2.0 wt % beryllium; a sum of cobalt and nickel of at least 0.2wt %; a sum of cobalt, nickel, and iron of at most 0.6 wt %; and balancecopper. This alloy is commercially available from Materion Corporationas Alloy 290. Alloy 290 has an elastic modulus of about 131 GPa; densityof about 8.36 g/cc; and a thermal conductivity at 25° C. of about 105W/(m·K).

As briefly mentioned above, one benefit to using BeCu alloys for therings of the present disclosure is the ability to perform ultrasonicinspection. Ultrasonic inspection is a useful and versatilenon-destructive testing technique which an be used for flawdetection/evaluation, dimensional measurements, materialcharacterization, and more. Ultrasonic testing is generally performedaccording to AMS 2154 Type I and Class A or EN 10228-4, Class 3equivalent. Depending on the size of the BeCu ring, it may be necessaryto pre-machine the ring prior to ultrasonic inspection to provide abetter surface finish for to ultrasonic inspection and allow for anymovement of the ring prior to finish machining.

The present disclosure has been described with reference to exemplaryembodiments. Modifications and alterations will occur to others uponreading and understanding the preceding detailed description. It isintended that the present disclosure be construed as including all suchmodifications and alterations insofar as they come within the scope ofthe appended claims or the equivalents thereof.

1. A process for making a metal ring from a BeCu alloy, comprising:preheating a BeCu alloy billet at a temperature of about 800° C. toabout 850° C.; forging the billet into a ring-shaped preform at atemperature of about 750° C. to about 850° C.; soaking the preform at atemperature of about 815° C. to about 835° C.; ring rolling the preformat a temperature of about 750° C. to about 850° C. to form a ring havinga wall thickness; solution annealing the ring at a temperature of about780° C. to about 800° C., immediately followed by quenching the ring;and heat treating the ring at a temperature of about 385° C. to about400° C.
 2. The process of claim 1, wherein the preheating occurs for aperiod of at least 8 hours.
 3. The process of claim 1, wherein thesoaking occurs for a minimum period of 2 hours.
 4. The process of claim3, wherein the soaking is performed for a period of at least 8 hours ifthe preform has cooled to a temperature of about 600° C. or less.
 5. Theprocess of claim 1, wherein the solution annealing occurs for a periodof at least 1.5 hours.
 6. The process of claim 1, wherein the heattreating occurs for a period of about 3 hours.
 7. The process of claim6, further comprising starting the about 3 hour period at a temperatureof about 393° C., raising the temperature to about 400° C., and heattreating the ring at the about 400° C. temperature for the remainingperiod of time.
 8. The process of claim 1, wherein the preheating andsoaking are each performed at a temperature of about 820° C.
 9. Theprocess of claim 1, wherein the ring rolling reduces the wall thicknessby at least 50%.
 10. The process of claim 1, wherein the solutionannealing is performed for a period of about 30 minutes forapproximately every 25 mm of wall thickness of the ring.
 11. The processof claim 1, further comprising air cooling the ring after both the ringrolling and the heat treating.
 12. A metal ring, comprising: a BeCualloy comprising about 1.6 wt % to about 2.0 wt % beryllium, wherein theBeCu alloy has: a 0.2% offset yield strength of at least 760 MPa; aRockwell C hardness of at least 27 HRC; and a percent elongation of atleast 6%.
 13. The ring of claim 12, wherein the BeCu alloy comprisesfrom about 1.8 wt % to about 2.0 wt % beryllium, or comprises from about1.8 wt % to about 1.9 wt % beryllium.
 14. The ring of claim 12, whereinthe BeCu alloy further comprises from about 0.2 wt % to about 0.3 wt %cobalt.
 15. The ring of claim 12, wherein the BeCu alloy furthercomprises from about 0.2 wt % to about 0.6 wt % lead.
 16. The ring ofclaim 12, wherein the BeCu alloy further comprises an amount of nickel,cobalt, and optionally iron such that the sum of (nickel+cobalt) isabout 0.2 wt % or higher, and the sum of (nickel+cobalt+iron) is about0.6 wt % or less.
 17. The ring of claim 12, wherein the BeCu alloy hasan electrical conductivity of at least 25% IACS.
 18. The ring of claim12, wherein the BeCu alloy has an average grain size of 0.1 mm or less,or wherein the BeCu alloy has a Rockwell C hardness of 27 HRC to about33 HRC.
 19. A process for making a metal ring, comprising: providing abillet made from a BeCu alloy comprising about 1.6 wt % to about 2.0 wt% beryllium; preheating the billet at a temperature of about 800° C. toabout 850° C. for a period of at least 8 hours; forming a ring-shapedpreform from the billet at a temperature of about 750° C. to about 850°C.; soaking the preform at a temperature of about 815° C. to about 835°C. for a period of about 2 hours to about 8 hours; ring rolling thepreform at a temperature of about 750° C. to about 850° C. until thepreform has a substantially uniform wall thickness, followed by aircooling; solution annealing the preform at a temperature of about 780°C. to about 800° C. for a period of at least 1.5 hours, immediatelyfollowed by quenching in a quench medium; heat treating the preform at atemperature of about 385° C. to about 400° C. for a period of about 3hours, followed by air cooling; and, mechanically machining the preformto form the metal ring having a desired shape.
 20. An amorphous metalcasting apparatus comprising a metal ring, wherein the metal ring ismade from a BeCu alloy comprising about 1.6 wt % to about 2.0 wt %beryllium, wherein the BeCu alloy has: a 0.2% offset yield strength ofat least 760 MPa; a Rockwell C hardness of at least 27 HRC; and apercent elongation of at least 6%.